Siemens 6RA70 specifications Fault Description

Fault

No.

Description
Cause as a function of fault value	Further information (r047.002 to r047.016)
(r047.001, r949.001 or r949.009 with acknowledged error)

25The average armature current required for the speed range from +7% to approximately +13% of maximum speed to cover the friction and/or steady-state load torque cannot be calculated

Possible cause:

•Drive with very little friction or very small integral-action time and, as a result of the very short measuring time, computational inaccuracies during evaluation

•Distorted or disturbed actual speed value

•Large flywheel mass that is coupled to the drive via long shaft with high torsion, possibly via a coupling with large amount of play

Possible remedy:

•Reduce P100 for duration of the optimization run to decrease the acceleration current applied during optimization and thus to lengthen the measuring time

26Load torque too high (nset =0% nmax results in nict ≥ 40% nmax) (actual speed value is averaged over 90 firing cycles, speed monitoring at ≥ 40% nmax does not start for 1s after application of speed setpoint of nset=0)

Possible cause:

•An excessively high load torque (in a positive or negative direction, e.g. suspended load) causes the drive to rotate (the speed controller parameters are parameterized according to the factory setting during this run)

•One of the armature current or torque limits is parameterized too low (the motor field may not be reaching full field strength fast enough with the result that the initial motor torque is too low)

•Maximum speed setting is incorrect

•Pulse encoder parameters are incorrect (P140 to P143)

•Parameters for tachometer adjustment are not correct (P741)

27Load torque is too high (nset=0% nmax results in EMF >100% setpoint EMF) (EMF monitoring at ≥ (P101 – P100 * P110) does not start for 1 s after application of speed setpoint of nset=0)

Possible cause:

•An excessively high load torque (in a positive or negative direction, e.g. suspended load) causes the drive to rotate (the speed controller parameters are parameterized according to the factory setting during this run)

•One of the armature current or torque limits is parameterized too low (the motor field may not be reaching full field strength fast enough with the result that the initial motor torque is too low)

•Maximum speed setting is incorrect

•Pulse encoder parameters are incorrect (P140 to P143)

•Parameters for tachometer adjustment are not correct (P741)

•Setpoint EMF settings are incorrect (P101, P100, P110)

28A steady-state actual speed corresponding to 0% of maximum speed cannot be reached within 0 s in speed-controlled operation (the speed setpoint/actual value difference averaged over 90 firing cycles must be <1.0% nmax for a total of 4s)

Possible cause: As for fault value 26

29The calculated armature circuit inductance is greater than 327.67 mH, therefore P111 = 327,67 mH has been set. All other parameters (the current controller parameters P155 and P156 too) have been set correctly despite that. (For the real armature circuit inductance in mH, see r047.i010).

Possible cause:

•e.g. field supply from the armature terminals

30The calculated armature circuit inductance is greater than 327.67 mH and the calculated armature circuit resistance is greater than 32.767 Ω, therefore P111 = 327,67 mH and P110 = 32,767 Ω has been set. All other parameters have also been set. However, the values of the current controller parameters P155 and P156 might differ from the optimum setting.

Possible cause:

•e.g. field supply from the armature terminals

9-18	Siemens Energy & Automation
	SIMOREG DC Master Base Drive Panel Operating Instructions